344 Britton : Studies of West Indian plants 



with great interest a roadside ditch full of these plants, some 

 densely pilose all over, some essentially glabrous. I could not 

 see at the time of collecting nor have I been able to see from 

 further study of the dried specimens, any other difference what- 

 ever in the two races. Both arc rayless, have identical achenes 

 varying from 2 to 4, with awns relatively of the same length, 

 leaves of the same shape and texture and involucral scales alike 

 From the environment and occurrence there was nothing to pre- 

 vent one coming from the seeds of the other. The plants as here 

 observed are not as stout nor as large-leaved as the figure of Dil- 

 lenius. The typical race of Bidens pilosa L. is then well named, 

 but it is apparently rare. 



Bidens laicantlia (L.) Willd. published by Linnaeus as Coreop- 

 sis leucantlia (Sp. PI. ed. 2. 1282), also a very common tropical 

 weed, has sometimes been regarded as a variety of B. pilosa. It 

 has white rays often 1.5 cm. long, and in life appears very different, 

 but herbarium specimens from which the rays have fallen are 

 often difficult to place. It commonly grows with the glabrous B. 

 pilosa, but perhaps more frequently in separate patches and in the 

 West Indies one frequently sees large areas inhabited by the one 

 to the exclusion of the other. At Kempshot, near Montego 

 Bay, Jamaica, they grew together in a small garden and I was 

 able to study them side by side ; here B. leucantha had the invo- 

 lucral scales spreading at flowering time, while those of the glab- 

 rous B. pilosa were erect. I am inclined to regard 'leucantha as a 

 distinct species. There is a race with undivided leaves. 



6. THE GENUS MALACHE B. VOGEL. 



Malaclie scabra was proposed by B. Vogel (Trew, PI. Select. 

 50. pi. 90. 1772) as the name of a mangrove-swamp shrub 

 common nearly throughout the West Indian region, subsequently 

 called by Cavanilles (Diss. 3: 136. pi. 46. f. 1. 1787) Pavonia 

 spicata, and by Swartz (Fl. Ind. Occ. 2: 121 5. 1800) Pavonia 

 racenwsa. Trew cites pre-Linnaean names for the plant, and gives 

 a detailed description and a beautiful illustration of it, especially 

 referring to Sloane, Hist. Jam. 221. pi. ijp. f. 2 ; Sloane's de- 

 scription and illustration are unmistakable for the species. Lin- 

 naeus does not appear to have had any name for it. 



